HAMILTON TOWNSHIP — Residents near Lake Lenape’s dam are being asked to sign up for emergency notifications after consultants surveying the dam found “voids in the earthen berm” between the spillway and the ruins of the nearby former mill building.
“We don’t know if they are large or small yet,” township Administrator Michael Jacobs said of the voids.
Once the crews from the engineering firm URS Corp. found the empty spaces about a month ago, Jacobs said, the firm suggested the township lower the water levels in Lake Lenape before any major storm.
This would allow the dam to better absorb storm runoff, Jacobs said Tuesday night, when he revealed the dam’s problems at a township meeting. Jacobs said the emergency discharges from lowering the water level have caused the lake level to fluctuate by several inches throughout the summer.
At Tuesday’s meeting, Mayor Amy Gatto asked residents living near the Lake Lenape dam to sign up with the emergency notification service Nixle. The “Township of Hamilton Police” account has used this service to publicize lake drawdowns.
Most recently, after heavy rains last month, the account announced Aug. 16 that the township would open the floodgates because the Great Egg Harbor River had crested above flood stage at Folsom upstream.
The Lenape dam is the largest in Atlantic County, according to U.S. Army Corps of Engineers records.
The agency classifies the 1879 structure as a high hazard, since it believes its failure would probably kill at least one person and cause significant property damage. It is the county's only high-hazard dam.
The 29-foot-high dam can hold 6,610 acre-feet of water, or almost three times as much as the county’s next largest, an Absecon dam operated by the Atlantic City Municipal Utilities Authority.
An acre-foot is 325,853 gallons, the amount of water that would cover one acre with one foot of water. It is about the amount used by a suburban household in a year.
The announcement is the latest in a series of problems for the dam.
Three 3- to 4-foot pipes at the base of the dam serve as floodgates. The county announced plans in July 2010 to spend as much as $1.1 million to replace the pipes, which had essentially worn out. The county and township agreed to share costs.
But an initial cofferdam built by contractor Agate Construction, of Dennis Township, to keep water away from the construction site failed the following March. Township police, fearing potential flooding, scrambled to warn about 50 residents downstream.
The dam stood, but its floodgates remained stuck open for months. That mostly drained the lake and curtailed boating for several days that June.
Township and county officials have since said they were contemplating suing Agate for incomplete work. “It is unacceptable the way it is, and the people, the citizens, will have recourse,” County Executive Dennis Levinson said Wednesday.
No case record for open litigation could be found Wednesday.
Meanwhile, officials said the dam remains safe.
“We would be taking much more precaution if there were any major issues, and that’s why we keep constant attention on the safety and effectiveness of the dam,” Gatto said.
“We don’t feel that it is a danger,” Levinson added. “The answer to that is, ‘hopefully not.’”
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